This invention relates to bulk feed tanks or bins for storing a dry, fluent material, for example, grain or ground corn products fed to livestock, and, more particularly, to indicators which quickly and accurately determine the level of feed in the tank or bin.
Bulk feed tanks are used on farms, feed lots, poultry houses, and similar locations to store the grain or other feed which is to be fed to livestock. Typically, the bin is elevated some distance above the ground and has an opening in its top through which grain is poured into the bin. A conveyor, such as an auger-type conveyor, is used to move feed from a delivery truck into the tank. The bin has an outlet formed at its bottom for the feed to fall, by gravity, into a conveyance, such as another auger conveyor, by which it is delivered to a poultry house, swine pen, or other feed site. In many operations, large quantities of feed are used. This means a bin is refilled every second or third day. Also, many operations have multiple bins some of which will be fuller than others and all of which must be monitored for feed level so the refilling operations can be organized for efficient refilling.
Because feed bins are elevated and made of metal, it is not easy to determine the level of feed in them. As a practical matter, the farmer or feed lot operator wants to know sufficiently far in advance when the quantity of stored feed is running low so he can arrange for delivery of more feed before he runs out. On the other hand, when the bin is being filled, the operator of the feed delivery truck needs to know when the bin is topping out so he can stop the loading conveyor before there is any spillage. In some operations, the bins have associated scales which provide readings to a central location. This allows the operator to determine how much feed has been removed from the bins so he can schedule filling operations accordingly. However, such operations are the exception. In most operations, the way to check feed level is to simply have someone climb a ladder and peer into the top of the bin. However, this method is impractical. If there are a number of bins, then every time an unloading occurs, someone must climb up the ladder and check the level to see if a refill point has been reached. During filling, the operator would be constantly up and down trying to insure he stopped the conveyor at the right time. If he had an assistant, the cost of operating the bin would increase. In either case, a great deal of reliance would be placed on the observer's ability to accurately gauge the fill level. Further, climbing up and down a ladder could be hazardous during inclement weather. Clearly, it would advantageous to be able to readily determine the bin fill level from the ground. Hatches or covers for the top opening which are operable from the ground are currently available; see, for example, our co-pending application Ser. No. 07/811,615, filed Dec. 23, 1991, so there is currently no need for anyone to be climbing up the bin.
Various efforts have previously been :made to provide a bin fill indicator which is readily observable by someone standing on the ground so they can determine the fill level without having to climb up the bin. See, for example, U.S. Pat. Nos. 4,936,245, 4,627,378, 3,542,982, 3,443,437, 3,290,938, and 3,279,078. While each of these prior art patents provides some type of fill level indication, none address the dual need as outlined above. In addition, certain of the patents have other drawbacks as well.
What would be helpful, therefore, is a bin fill indicator which is simple and reliable in operation and provides an accurate indication of the level of material in the bin both during filling and as the bin is unloaded.